This invention relates generally to poppet valves, and more particularly to poppet valves in fuel supply systems.
In many valves, for example poppet valves for fuel injectors, an actuator is used to pull a poppet type spool to one of at least two positionsxe2x80x94one in which the spool engages a seat (to open or close the valve) and one in which the spool is not engaged with the seat. In this type of valve, control of the spool""s movement toward and away from its seated position is desirable. For example, it is advantageous to have the spool unseat very quickly when the valve is to move to the open valve position, in order to fully open the valve so as to get the full desired fluid flow as quickly as possible.
This invention is directed at overcoming one or more of the above problems.
In one aspect of the invention, a poppet valve includes a valve body including a bore therein. The bore includes an inlet port for admitting fluid to the bore. The bore also includes at least one seat. A spool in the bore slides between an open position in which the spool is spaced from the seat, and a closed position in which the spool is engaging the seat. The spool and the bore at least partially define an upstream fluid flow volume in fluid communication with the inlet port. The seat is also in fluid communication with the inlet port, via the upstream fluid flow volume. The upstream fluid flow volume is configured such that when the spool is at the open position and fluid is flowing from the inlet port to the seat via the upstream fluid flow volume, an effective flow area for fluid entering the upstream fluid flow volume from the inlet port does not significantly exceed an effective flow area for fluid passing between the spool and the seat.
In another aspect of the invention, a poppet valve includes a valve body including a bore therein. The bore includes an inlet port for admitting fluid to the bore. The bore also includes at least one seat. A spool in the bore slides between an open position in which the spool is spaced from the seat, and a closed position in which the spool is engaging the seat. The spool and the bore at least partially define an upstream fluid flow volume in fluid communication with the inlet port. The seat is also in fluid communication with the inlet port, via the upstream fluid flow volume. The valve comprises pressure controlling means for keeping static fluid pressure from developing in the upstream fluid flow volume when the spool is at the open position and fluid is flowing from the inlet port to the seat via the upstream fluid flow volume.
In yet another aspect of the invention, a method is provided for configuring a poppet valve for use in a valve including a valve body. A bore having an upstream wall portion and a downstream wall portion is formed in the valve body. A fluid passage is formed in the valve body terminating at an inlet port in the bore to fluidly connect the fluid passage with the bore at via inlet port. A seat is formed in the bore between the upstream wall portion and the downstream wall portion. A spool having a non-uniform diameter is configured to be able to engage with the seat in the bore so as to block fluid communication past the seat in the bore. The spool is slideably disposed the spool in the bore, such that the spool is slideable between a first position in the bore in which the spool is spaced from the seat so as to provide fluid communication past the seat in the bore, and a second position in the bore in which the spool engages with the seat so as to block fluid communication past the seat in the bore. A downstream volume is formed between the downstream wall portion and the spool surface such that when the spool is in the first position a first effective flow area for fluid passing between the spool and the seat has a first predetermined value. An upstream volume is formed between the upstream wall section and the spool surface. The upstream volume is formed to be partially defined by the inlet port and in fluid communication with the fluid passage, such that a second effective flow area for fluid entering the upstream volume from the inlet port has a second predetermined value not significantly greater than the first predetermined value.